2019
Cover crops and other strategies to manage glyphosate-resistant horseweed (marestail)
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Contributor/Checkoff:
Michigan Soybean Committee
Category:
Sustainable Production
Keywords:
AgricultureCrop protectionHerbicide
Parent Project:
This is the first year of this project.
Lead Principal Investigator:
Christy Sprague, Michigan State University
Co-Principal Investigators:
Project Code:
1916
Contributing Organization (Checkoff):
Michigan Soybean Committee
$27,333
Institution Funded:
Michigan State University
$27,333
Brief Project Summary:

Horseweed (marestail) continues to be the #1 weed escape in Michigan soybean fields. Resistance to ALS-inhibitors (Group 2), glyphosate (Group 9), and in many cases resistance to both of these classes of herbicides leaves no options for postemergence control of horseweed in Roundup Ready or non-GMO soybean. In addition to multiple herbicide-resistance, prolonged emergence, changes in tillage practices and capabilities of long distance seed dispersal have also contributed to the increased prevalence of horseweed in many of Michigan’s soybean fields.

In 2018, with funding by MSPC and Project GREEEN, we were able to conduct the first year of a two-year research project examining the impact...

Unique Keywords:
#weed control
Information And Results
Project Deliverables

Information from this research will be used to further develop and demonstrate recommendations for control of glyphosate-resistant horseweed to Michigan soybean growers. These recommendations will be used to further refine and update the “Herbicide-resistant (marestail) in Michigan: Keys to management in no-till soybean” factsheet that is posted on the MSUWeeds.com website and in the MSU Weed Control Guide for Field Crops (E0434). This bulletin is sold to over 1300 farmers, dealers, and weed management influencers. In addition, we will continue to hold meetings throughout the state to make growers aware of the issues and the options for control of herbicide-resistant horseweed. The awareness from our outreach efforts will continue to be important to identify and manage this troublesome weed.

Final Project Results

On September 17, 2019, there was a field day held at this location where approximately 25 farmers and ag retailers attended. We would like to thank MSPC and Paul Gross for hosting this field day. The information was valuable for farmers in this area to learn more about horseweed management strategies and the potential use of cover crops to help manage glyphosate-resistant horseweed. The results from these soybean trials were critical to updating the “Herbicide-resistant horseweed (marestail) in Michigan: Keys to management in no-till soybean” factsheet that is in the 2020 MSU Weed Control Guide for Field Crops and posted on www.MSUWeeds.com. This factsheet was also printed in the 2019 Michigan Soybean on-Farm Research bulletin. Results from these trials have also been, and will continue to be, presented at several winter extension meetings, including the MSPC sponsored SMaRT meetings. This research has been important to provide effective information to soybean growers to help manage this troublesome economically significant weed problem. It will also provide additional control strategies and herbicide options to aid in the management of a weed that has the ability to develop resistance to multiple-herbicide sites of action.

The United Soybean Research Retention policy will display final reports with the project once completed but working files will be purged after three years. And financial information after seven years. All pertinent information is in the final report or if you want more information, please contact the project lead at your state soybean organization or principal investigator listed on the project.